Embodiments of the present specification relate to magnetic resonance imaging (MRI), and more particularly to wireless actuation of MRI coils.
As will be appreciated, when a substance such as human tissue is subjected to a uniform magnetic field (polarizing field B0), individual magnetic moments of spins in tissues attempt to align with the applied polarizing field. However, the individual magnetic moments of the spins precess about this polarizing field in random order at their characteristic Larmor frequency. If the substance or tissue is subjected to a magnetic field (excitation field B1) which is in the x-y plane and the magnetic field is near the Larmor frequency, the net aligned moment, or “longitudinal magnetization”, MZ, may be rotated, or “tipped,” into the x-y plane to produce a net transverse magnetic moment, Mt. Further, a signal is emitted by excited spins after the excitation field, B1, is terminated. This emitted signal may be acquired and processed to form an image.
Moreover, when utilizing these emitted signals to produce images, magnetic field gradients (Gx, Gy, and Gz) are employed. Typically, a region of interest that is to be imaged is scanned by a sequence of measurement cycles in which these magnetic field gradients vary based on a particular localization method being used. Resulting sets of received nuclear magnetic resonance (NMR) signals are digitized and processed to reconstruct an image using known image reconstruction techniques.
Over time, magnetic resonance (MR) systems have progressed from low-field, single-channel systems toward high-field multi-channel systems, allowing highly accelerated parallel imaging. A number of channels in MR scanners has been increasing rapidly, resulting in a large number of cables running from the system to MRI coils. The increasing number of cables leads to longer patient set up time as well as patient discomfort during imaging as these MRI coils are placed around the patient. Therefore, there is an ongoing effort to enable one or more aspects of an MR system to be wireless.